1. Field of the Invention
The present invention relates to a compact fluorescent lamp unit that is adapted for use as a direct replacement for an incandescent type lamp in a lighting fixture.
2. Description of the Related Art
A compact fluorescent lamp unit is widely used for residential and commercial illumination. In Japanese patent document (kokai) 61-168856(1985) a compact fluorescent lamp unit of this type is disclosed. The compact fluorescent lamp unit has a saddle shaped glass bulb which contains a pair of filament coils disposed in each bulb end. The filament coil contains an emitter for enhancing thermionic emission. The lamp unit also has a lighting circuit which is enclosed in a plastic housing, together with the bulb. A threaded member is fitted on a base portion of the housing for permitting the lamp unit to be operated with on an AC power source. Inside the housing, a space is provided for the bulb and the lighting circuit. A support member for supporting both bulb ends is disposed in the space.
When the emitter of the filament coils is dissipated at the end of the life time of the lamp unit, it abnormally raises temperature of the filament coil. Excessive heat deteriorates the support member holding the lamp bulb ends which may lead to fumming or fire for the worst case.